You can think through the maths but you don't have to. This is one of those cases were pattern recognition is enough and no more thought is needed. That is to s

You can think through the maths but you don't have to. This is one of those cases were pattern recognition is enough and no more thought is needed. That is to say, a mathematician should (and has no excuse not to) have seen Euclid's illustration of Pythagora's theorem which the journal cover is a very obvious representation of, so there should be no confusion.